On a recent drizzly Tuesday morning, a small group of ink enthusiasts—already rain-slicked, under umbrellas and ponchos—stood on Gapstow Bridge, in Central Park, admiring a brilliant-pink pokeweed bush. The Park was the first stop on a five-hour foraging trip that would take them up to Hudson Heights, to collect foliage and trash, which they would cook, to make ink. Their guide, Jason Logan, the founder of the Toronto Ink Company, was in town for the launch of his book, “Make Ink: A Forager’s Guide to Natural Inkmaking.” At a reading in the West Village, he had asked the audience if anyone wanted to go foraging. The city offers some attractive ingredients: acorns, wild grapevines, beer caps, feathers, subway soot.

Logan, who is forty-six, became interested in ink about twenty years ago, when he was living in New York, working as an illustrator for newspapers and magazines. He’d burned through a bottle of black-walnut ink, which he’d bought at Pearl Paint, on Canal Street. When he returned for more, the ink was gone. “Then I found black walnuts on my way to work one morning and realized it was easy to make my own deep, rich, delicious ink,” he said.

On the bridge, Logan addressed the foragers, four women of varying ages. He has curly gray hair and was wearing a windbreaker in almost the same hue. “I’m kind of in love with gray,” he said. “It’s interesting for me, too, in terms of ink. Gray is ashes suspended in water.” Logan speaks like a laid-back chemist, using words like “petrichor,” the earthy scent produced when rain falls on dry soil. He carried a backpack filled with ink pots and collection bags.

“That is so bright!” Julia Norton, an artist who teaches a pigment class, said, examining the pokeweed’s fuchsia stems.

“It’s so beautiful it’s hard to believe it just grows like this,” Logan said. “Pokeberry ink was most famously used by Civil War soldiers to write love notes.”

Jessica Maffia, another artist, was picking berries. “I still can’t believe the serendipitous nature of this,” she said. “I have a garbage bag full of pokeweed in my studio! I swear, I just wrote on my calendar, ‘Learn how to make pokeberry dye.’ ”

The rain was letting up—the sky became a misty gray—and Barbara Abramson, who teaches art and design, identified a sumac bush just south of the bridge. “They’re a weed. They’re everywhere and they’re a bit menacing,” Logan said.

“They’re ferocious,” Abramson added, admiringly.

“Let’s eat a bit of sumac,” Logan said, passing out small scarlet berries. He ate his first. “It’s tart, with a lot of Vitamin C,” he noted. “Also tannins. The dyers love it. I use the berries to make a pinkish ink. Add iron and you get a complicated kind of black.” A red cardinal streaked across the sky, and everyone looked up. “You know, for many birds, their coloring comes from what they eat—fruit, plankton,” Logan observed. “Flamingoes, they’re basically ink-makers.”

The foragers headed across the Park, toward the 1 train at Fifty-ninth Street. One stretch offered up goldenrod (good for yellow ink, Logan said); burdock (“hated by gardeners, but the root makes for an interesting orangish color when roasted”); lamb’s-quarter (“faint magenta”); and hawthorn berry (“uninkable, as far as I know”). Ground-level materials included a purple drinking straw and a cigarette butt. “Tobacco actually makes a beautiful coppery green,” Logan said. “I discovered this foraging at a children’s birthday party.” He praised the local loose change: “The American penny is amazing. It’s copper and it oxidizes. It’s gorgeous. We don’t make pennies anymore in Canada. I’m sad about that.”

By the time the foragers left Central Park, the pockets of Logan’s jacket were already bleeding pink. After finishing uptown, a few hours later, they went to Maffia’s apartment, to make ink. One batch was pure pokeberry juice (vivid magenta). Another included five varieties of acorn boiled with rust from various sources—nuts and bolts, wire, brackets—and a drop of gum arabic. It came out a complicated silver-gray. Logan spread a range of ink pots on Maffia’s kitchen table. He dipped the bottom of a glass jar into the rust-and-acorn ink and pressed it onto a piece of paper, making a silvery circle. “Look at our day,” he said. “Now, that, to me, is the blood of New York.” ♦

Published in the print edition of the November 12, 2018, issue, with the headline “Wet Ink.”